Breathomics and its Application for Disease Diagnosis: A Review of Analytical Techniques and Approaches
Raquel Cumeras, Xavier Correig in Volatile organic compound analysis in biomedical diagnosis applications, 2018
Some researchers collect exhaled breath condensate (EBC), which is a biofluid obtained non-invasively after collecting and cooling the exhaled air (Baraldi et al., 2009; Carraro et al., 2007; Ibrahim et al., 2013). Typically, the condensate is collected via a sampling device fitted with a condenser and a saliva trap. A major advantage of analyzing EBC is that it captures both volatile and non-volatile metabolites (Nobakht et al., 2015). The EBC is collected over a period of 15 or more minutes and its composition is believed to reflect that of the fluid lining the airways (Carraro et al., 2007). Exhaled breath vapor/condensate (EBV/EBC) collection, has been described in a widely cited research paper by Martin et al. (2010). The study involved the use of a solid phase microextraction (SPME) fibre fitted inside the commercial breath collection device, namely the RTubeTM. The SPME adsorbed sample was then desorbed to a gas chromatography mass spectrometry (GC-MS) assembly for analysis. The test indicated a presence of limonene and related metabolites such as pinene, myrcene and terpinols from breath samples of individuals who had consumed lemonade. The study also showed a great potential for detecting compounds more relevant to medical diagnosis.
Alternaria
Dongyou Liu in Laboratory Models for Foodborne Infections, 2017
For the evaluation of mycotoxin production by Alternaria, analytical methods based on chromatography are often used for their extraction and detection from the food matrices (Figure 30.1). Usually, a solvent extraction from solid foods with organic solvents, such as dichloromethane, methanol, acetonitrile, or ethyl acetate, is required, although an acidic extraction or a further acidification step is preferable to increase the recovery for TeA.33 Cleanup procedures are necessary when a complex matrix is involved. Successive steps of solvent partitioning, solid phase extraction (SPE) columns, or solid phase microextraction are common cleanup techniques used in most food matrices.24
History and Sources of Essential Oil Research
K. Hüsnü Can Başer, Gerhard Buchbauer in Handbook of Essential Oils, 2020
In static HS analysis, the liquid or solid sample is placed into a vial, which is heated to a predetermined temperature after sealing. After the sample has reached equilibrium with its vapor (in equilibrium, the distribution of the analytes between the two phases depends on their partition coefficients at the preselected temperature, the time, and the pressure), an aliquot of the vapor phase can be withdrawn with a gas-tight syringe and subjected to gas chromatographic analysis. A simple method for the HS investigation of herbs and spices was described by Chialva et al. (1982), using a blender equipped with a special gas-tight valve. After grinding the herb and until thermodynamic equilibrium is reached, the HS sample can be withdrawn through the valve and injected into a gas chromatograph. Eight of the obtained capillary gas chromatograms are depicted in the paper of Chialva and compared with those of the respective essential oils exhibiting significant higher amounts of the more volatile oil constituents. However, one of the major problems with static HS analyses is the need for sample enrichment with regard to trace components. Therefore, a concentration step such as cryogenic trapping, liquid absorption, or adsorption on a suitable solid has to be inserted for volatiles occurring only in small amounts. A versatile and often-used technique in the last decade is solid-phase microextraction (SPME) for sampling volatiles, which will be discussed in more detail in a separate paragraph. Since different other trapping procedures are a fundamental prerequisite for dynamic HS methods, they will be considered in the succeeding text. A comprehensive treatment of the theoretical basis of static HS analysis including numerous applications has been published by Kolb and Ettre (1997, 2006).
Liquid chromatography coupled to mass spectrometry for metabolite profiling in the field of drug discovery
Published in Expert Opinion on Drug Discovery, 2019
Javier Saurina, Sonia Sentellas
As a further step, extraction techniques can be applied to recover the desired metabolites without unwanted interferences. Liquid extraction with organic solvents and hydro-organic mixtures has been widely used, in which the affinity of drug metabolites towards the extraction solvents is the basis to obtain high recoveries. Solid phase extraction (SPE) offers great analytical possibilities in metabolite profiling because of its versatility. A great variety of (ad/ab)sorbents are commercially available which can be chosen depending on the characteristics of metabolites and matrices. In this regard, the same kind of mechanisms taking place in the chromatographic separation (see below) can be exploited here for cleanup and preconcentration purposes. As a miniaturized version, solid phase microextraction (SPME), based on the retention and concentration of analytes on absorbent fibers of a wide range of materials, have also been introduced for the treatment of biological samples [28].
Ultra-preconcentration of common herbicides in aqueous samples using solid phase extraction combined with dispersive liquid–liquid microextraction followed by HPLC–UV
Published in Toxin Reviews, 2021
Toraj Ahmadi-Jouibari, Negar Noori, Kiomars Sharafi, Nazir Fattahi
Sample preparation is one critical step of an analytical procedure and an integral part of any analysis. Optimized sample preparation is necessary, not only to reduce the time taken but because each step adds a potential source of error. The amount of sample preparation needed depends on the sample matrix and the properties and level of analyte to be determined. The determination of trace contaminants in complex matrices, such as biological samples and highly saline solutions, often requires extensive sample extraction and preparation regimes prior to instrumental analysis (Ma et al. 2018, 2019). Several techniques have been developed for the extraction and preconcentration of contaminants from aqueous samples, such as solid-phase extraction (SPE) (Rivoira et al. 2015, Wang et al. 2019), solid-phase microextraction (SPME) (Mirzajani et al. 2017, Pei et al. 2019), liquid–liquid extraction (LLE) (Duca et al. 2014), continuous sample drop flow microextraction (CSDFME) (Karimaei et al. 2017), homogeneous liquid–liquid extraction (HLLE) (Ebrahimzadeh et al. 2007), and liquid-phase microextraction (LPME) (Yilmaz and Soylak 2016, Reclo et al. 2017).
Identification of odor biomarkers in irradiation injury urine based on headspace SPME-GC-MS
Published in International Journal of Radiation Biology, 2021
Xin Wu, Tong Zhu, Hongbing Zhang, Lu Lu, Xin He, Changxiao Liu, Sai-jun Fan
Urine is stable, easy to collect and noninvasive, and it is widely used in clinical practice. However, due to low concentrations and various interferences including water, the analysis of VOCs is restricted, so it is very important to enrich the sample. Solid phase microextraction (SPME) has high extraction efficiency, a high pre-concentration factor and is easily automated (Ghorbani et al. 2019; Jalili et al. 2020). These advantages make it very popular, especially in combination with gas chromatography-mass spectrometry (GC-MS) with high resolution and high sensitivity, which greatly promotes the analysis of VOCs in urine. Nowadays, metabolomics based on SPME-GC-MS has been used for urine VOCs analysis of many diseases, such as cancer, autism and gastrointestinal diseases (Cozzolino et al. 2014; Gundamaraju et al. 2017; Deev et al. 2020).
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